A bicycle derailleur is basically provided with a base member, a chain guide, a linkage assembly and a first adjusting member. The chain guide is pivotally supported with respect to the base member between a retracted and an extended position. The linkage assembly includes a first link coupled to the base member about a first pivot axis and coupled to the chain guide about a second pivot axis. The linkage assembly includes a second link coupling the base member to the chain guide. The second link is farther from the bicycle frame than the first link when the base member is mounted to the bicycle frame. The first adjusting member is movably attached to the first link. The first adjusting member is configured to contact one of the base member and the chain guide to restrict movement of the chain guide at one of the retracted and extended positions.